Means and dies for drop-forging crank shafts and process of forming crank shafts



July 3, 1923. 1,460,720

H H. KEEP Ts MEANS AND DIES FOR DROP FORGING ORA SHAFTS AND PROCESS OF RMING- CRANK SHAFTS Filed Se t, 5, 1919 3 Sheets-Sheet l lV/i" WITNESSES I INVEN'R'OR.

HARRY H. KEEPoms July 3, 1923. 1.469.720

' H) H. KEEPORTS MEANS AND DIES FOR DROP FORGING CRANK SHAFTS AND PROCESS OF' FORMING CRANK SHAFTS Filed Sept. 5, 1919 A 3 Sheets-Sheet 2 nwrEAqzuz fiAR/QY H. Kaspar/s W1 TNESSES j BY Juiy 3, 1923.

H.H.KEEPORTS DROP FORGING CRANK SHAFTS AND PROCESS OF FORMI N G C R A NK SHAFTS Filed Sept. 5, 1919 5 Sheets-Sheet 5 WITVESES VENTOR.

I HARR .lififpopns Patented July 3, 1%23.

NI a a ea hdhdfizd i I Q E.

mnelvs AND mas non nnor roneme CRANK SHAFTS AND r noonss or FORMING CRANK SHAFIS.

Application filed September 5, 1919. Serial No. 321,933.

To all whom it .wwry concern:

Be it known that I, HARRY H. KEEPoR'rs, a citizen of the United States, residing at Detroit, county of Wayne, State of Michigan, have invented certain new and useful Improvements in Means and Dies for Drop- Forging Crank- Shafts and Processes of Formin lowing IS a specification.

This invention relates to improve means and dies for drop forging crank sha s and to the process of forming the crank shaft.

The object of the invention is to provide improved dies and methods of drop forging crank shafts whereby the structure of the shaft will not be strained or distorted by twisting after the forgingoperation.

Objects which relate to details will appear from the description to follow.

"The objects of the invention are accom plished by the devices and means described in the following spec fication. The invention is defined and pointed out in the claims.

A structure which is a preferred embodi-' ment of the invention is clearly illustrated in the accompanying drawings, forming a part of this specification, 1n-wh1ch:

Fig. I is a plan view of the dies for drop forging the crank shaft. v

Fig. II is an elevation of the dies somewhat separated, looking against the lower side of Fig. I.

Fig. III is a vertical detail sectional View of the dies with a completely forged crank shaft disposed therein, the same being taken on line 3-3 of Figs. I, IV, parts of the crank throws being shown by dotted 111188 Fig. IV is a detail view of the operating faces of the top and bottom dles 1 and 2 placed side by side.

Fig. V is an illustration of the bar from which thecrank shaft is formed.

Fig. V1 is an outline plan view of the rounded bar after the first 'bendin and shaping operation performed by the die, the

oblique impression on the under side being.

shown by dotted lines and shading being omitted. a

Fig. VII is an elevation view of the bar after such preliminary bending and shaping operation.

Fig. VIII is an elevation perspeotlve View of the completely formed crank shaft ready for machining.

Fig. IX is a detail sectional elevation on Crank Shafts, of which the folview online 12-12 of Fig. VIII,

. line 9-9 of Fig, VIlIishowing one of the crank throws.

Fig. X is an enlarged detail sectional view on line 10-10 of F 1g. VIIL'showing a detail of one of the crank pins and the next succeeding throw.

Fig. XI is an end elevation view of this complete crank shaft.

Fig. XII is an enlarged detail sectional showing the cross sectional form of one of the crank arms.

Fig. XIII is a detail sectional view on the edge portion of the bottom die, taken on a line corresponding to line 13-13 of Fig. IV, showing the contour of the integral projection.

Fig. XIV is a detail view on the edge ortion of the die, taken on line 1414 of Fig. IV, showing the incline and shape of the die at that point, it being in the opposite direction to that appearing in F ig. XIII, showing the contour of the integral projection 9.

In the drawing, similar numerals of reference refer to similar parts throughout the severalviews, and thesectional views are taken looking in the direction of the little arrows at the ends of the section lines.

y invention relates particularly to dies and means for forming six throw crank shafts having three crank bearings, one hearing at each end and one at the middle, and generallyto any others involving similar manufacturing conditions.

In the rocess of making my improved crank shaf t I'subject the bar to a die action which forms the first and sixth crank throws preliminary operation.

This operation is performed in the edge die of my improved die blocks, and when this is complete the bar is moved to the second die recess or im ression, the upwardly projectingfirst an sixth throws and the downwardly projecting third and fourth throws being turned into a horizontal plane. The action of the second die or recess or mepression is to deflect the first and sixth and the balance of the blank moves down- In this behalf, the terms ward giving the result as stated, with the second and fth recesses in the bottom die.

It will be seen that by this method there is substantially no stretching of the metal as distinguished from the stretching due to bending after the first forming operation...

The arms of the different cranks are simply bent intoosition and form as seen in Figsf X and l without undue strain on the metal. At the same time these throws are forged, a; portion of the bar is partially upset ready for the final upsetting operation to form the integral flange.

0f course, after the crank shaft is forged, the fin is trimmed ofi and the shaft is subjected to finishing action on the die. The shaft after the fin is trimmed off in the trimming dies is. replaced in the final forming die and is submitted to further action thereof to finish the forging. The die is specially formed in various articulars to enable it to handle alloy stee up; down and lateral are only relative, and T describe the structure in the most convenient arrangement. The dies might all, of course, be operated horizontally, or the bottom die might become the top die. For the purposes of defining the invention, these terms will be regarded only as relative.

To make clear the general description above given, I will proceed to describe specifically the operations in conjunction with a specific embodiment of the invention appearing in the drawing. The top die 1 and bottom die 2 have two independent die surfaces, one at the edge which I will call the edge die and the other main die surfaces, which completes the forging of the shaft. The shaft andbar ldesignate by letter A, and the different crank throws andbearings by reference. characters A A A A A and A, the indexnumbers indicating the number of the crank throws.

Incarrying out my invention, I place the bar A, see Fig: V, between the edge dies, see particularly igs. TI and TV, and sub- 7 ject it to bending and prcliminary'forming and shaping action. The first and sixth crank throws, A and A, are bent upwardly into the depressions 4 and 6 on the top die by the PI'OWCtlOIlS 8 and 5 on the bottom die, and the third and fourth crank throws, A and A, are defiecteddownward by the projections 72 and'9 on the top die-cooperating into the depressions 8 and 10 on the bottom die'and the bar is slightly reduced in one direction and formed for the crank pins A and A of the second and fifth crankthrows by the projections 11'12 and iii-14 on the top and bottom dies respectively, see Fig. H. At the same time the end of the bar is somewhat upset and formed and prepared for the. final forgin and upsetting operations to form the ange integrally with the shaft.

In the handlin of alloy steel the projections 3 5 and 9 are disposed at an oblique angle to the longitudinal line of the bar and the corresponding depressions are also disposed at an oblique angle to permit the correct and proper shaping or forming of the alloy steel bar, and the central per-.

tions and end portions of the die of the edge dies beyond the projections 3-5 are in.- clined, as indicated by the line in Figs. XIII and XIV, for the same purpose or proper and correct shaping. An inspection of Fig. VI shows the imprint of the projections on the bar and how they make the formation. and forging easier when the bar is passed to the second die. If impressions were at right angles to the bar they would be oblique to'the shaft bearings after bending. I

\Vhere ordinary carbon steel is used, the disposition of these projections and depressions at an oblique angle is not a necessity. They may stand at right angles. VJhen the barhas taken the preliminary form seen .in Fig. VII, it is laiddo'wn in the main die, which, in all its parts, is made to conform to the shaft and subjected. to the action of completely drop forging the same. This action carries the second and fifth crank pin bearings down in the vertical plane of the shaft to their required positions and the intermediate crank arms accordingly without any particular stretcl'iin of the same (aside from what o'ccursin'ben ing), and the first (A and'sixth (AM-and the third (A and fourth (A crank throws are deflected relatively to the shaft upwardly through an angle of thirty de' grees so that they stand at an angle of sixty degrees to the vertical on each side, which distributes the crank throws in proper reposition of the crank throws and arms ap-' pears in Fig. XI, Fig. Xll is a cross section of one of the crank arms. Fig. XIII shows the inclination to accommodate the dies to the handling of alloy steel, which is much more highly resistant to the forging proc-' ess than carbon steel.

In Fig. VIII I show the crank shaft in top and bottom dies of the complete molds.-

This can best beunderstood by examining the-completed crank shaft. I have indicated on Figs. IX and X the line of parting between thetop and bottom dies preferred by me, th'elongitudinal parting being indicated by dotted and full lines on Fig. VIII. This parting may be considerably varied. I show the form which I have found to be hi hly efif'ective.

In Fig. XII I show the forming projections for forming the first and slxth crank throws, inclined, with the inclination of the body of the-die indicated by dotted lines, and in Fig. XIV I show the corre-' sponding inclination for. the third; and fourth throws. In Fi .VI the inclination of the impressions made by the projections and depressions are fully indicated in the plan view, those on the under side being indicated by the dotted lines.

1 By pursuing, this method in the forging,

of crank shafts, undue stretching of the metal is avoided and a six throw] three bearing shaft is quickly and effectively formed. It will be observed that by the method I have pursued the stretching of the, metal substantially all occurs in the ed e die and the crank pin bearings, as wel as the shaft bearings, are all substantially located'and rough formedin the edge dies. When the blanked bar has assed to the main die, the work to'be per ormed is substantially. the final bending and the complete forging of all .of the crank throws,

that bendinglbein "through an angle of sixty degrees in eac instance, which is the angle of bending and forging from the vertical central plane, and that there is substantially noupsetting or stretching of the metal between the crank pin bearings and the shaft bearings after the rough shaping in the edger die. The only stretching that occurs is that incident tobend ngand complating the forming in the 'finaldie. This -1s of great consequence in securing an efiec tive and efiicient forging of the shaft. The

metal is notwe'akened, and by placing the rojections and depressions at the angle a harof alloy steel can be readily formed into a crank shaft.

- My improved crankshaft is formed with I long arms or Webs between. the first crank pin and the second, and the second crank pin and the third, and the fourth crank pin and the fifth, and the fifth crank pin and the sixth, in substantially rectangular form. The shorter side of such web or arm in each instance. is inclined sufliciently fordraft from the die, the minimum being distributed symmetrically about the shaft,

it is necessary to project the metal on each balance. By this method it is possible to preserve av substantially rectangular cross section of these longarms or webs which insures most economical distribution of metal for carrying the strain. I

- I have described the form preferred by me, and which I desire to claim specifically- I also desire to claim the samebroadly as pointed out in the appended claims.

'Having thus described my invention, what I claim as new and desire to secure by Letters Patent is: I

. 1.- Theprocess of forming and drop forging a six-throw crank shaft. with end and central bearing parts consisting "in first de- -flecting in vertical planes and forming the arm past .the center sufficiently to insure the crank throws, then turning the partially formed bar so, that the'first and sixth,-and

and fifth crank pins and arms to their proper position and simultaneously bend- '100 third and fourth'crank throwsfar'e in a ing the first and sixth-crank throws to defiect them relatively upward thirty degrees to a point sixty degrees to one side of the vertical and the third and fourth crank" throws relatively upward thirty degrees to a point sixty degrees to the opposite side of the vertical, as specified.

2. The process of forming and "drop forg ing a six-throw crank shaft with end and central bearing parts consisting in first defleeting in vertical planes 'andforming' the first and sixth crank throws by upward deflection, and the third and fourth crank throws by downward deflection of the metal and rough forming the bearing pins and arms of second and fifth crank throws, then turning the partially formed bar so that the first and sixth, and third and fourth crank throws are in a horizontal plane, and thereafter deflecting the shaft to form the second and fifth crank pins andarms to their proper position, and bending'the first and sixth crank throws to deflect them relatively upward thirty degrees to a point sixty degrees to one side of the vertical and the third and fourth crank throws relatively upward thirty degrees to a point sixty degrees to the opposite side of the vertical, as-

specified. v

3. The process of forming and drop forg ing a three'bearing six-throw crank shaft, consisting in deflecting in vertical planes and forming the first and, sixth crank throws by upward, and fourth crank throws simultaneously-by downward deflection, and rough forming the pin bearings and arms of the second and fifth crank throws, then acting upon the blanked-bar at right angles to the first (l -i:

rection and carrying all the arms and bearings simultaneously to their roper relation in the finishing die, as speci ed.

4:. The process of forming and drop forging a three bearing six-throw crank shaft consisting indefiecting in vertical planes,

and forming the first and sixth crank throws in a suitable die, and thereafter actingupon the bar at right angles to the first'direction' and carrying the arms and hearings to their proper relation in the finishing die, as specified.

6. Dies for the forming ofa crank shaft comprising depressions and projections with obliquely arranged surfaces for deflecting the first and sixth crank throws in one direction and the third and fourth crank throws in an opposite direction in the same plane,

and a finishing die conformed to the form of the shaft and arranged to deflect'the secend and fifth crank pins, throws and arms to their proper position and forge all crank arms and pins, as specified.

7. Dies for the forming of a crank shaft comprising. depressions and projections with obli uely arranged surfaces for deflecting the rst and sixth crank throws in'one direction and the third and" fourth crank deflection and the third throws in an opposite direction in the same beingin planes oppositely inclined to the face of the die, and a'finishing die conformed to the form of the shaft and arranged to deflect the second and fifth crank throws to their proper position and forge all crank arms and pins, as specified.

8. Dies for the forming of a crank shaft comprising'depressions and, projections for deflecting the first and sixth crank throws in one direction and the third and fourth crank throws in an opposite direction in the same plane, and a finishing die conformed to the form of the shaft and arranged to deflect the second and fifth crank throws to their proper position and forge all crank arms and pins, as specified.

9. Dies for the forming of a crank shaft comprising depressions and projections with obliquely arranged surfaces for deflecting the first and sixth crank throws in one direction and the third and fourth crank "throws-in an opposite direction in the same, plane, and a finishing die conformed to the form of the shaft and arranged to deflect the second and fifth crank throws to their roper position, as specied.v

10. ies for the forming of a crank shaft comprising depressions and projections for deflecting the first and sixth crank throws in one direction and the third and fourth crank throws in an opposite direction in the same plane, and a finishing die conformed to the form of the shaft and arranged to deflect the second and fifth crank throws to their proper position, as specified.

11. Diesfor the forming of a crank shaft having three .crankthrows between the shaft bearings comprising depressions and projections for deflecting the first and. third crank throws and pins in opposite'directions and a finishing die conformed to the form of the shaft and arranged to deflect the second crank throw and shaft hearings to, proper position in relation to the said first and third crank pins In witness whereof, l have hereunto set my hand and seal in the presence of two witnesses.

HARRY H. KEEPQRTS. [as] v Witnesses:

LUELLA G Gnnrznrrnrn, Greece 3. "Increases.

plane, the surfaces at the center and ends 7 

